Many fresh produce products are harvested and packaged in the field. These produce products include, but are not limited to, berries, such as strawberries, grapes, mushrooms, radishes, tomatoes, including cherry tomatoes, broccoli florets, lightweight tree fruit, and other fruits and vegetables. Many of these produce items require substantial post-harvest cooling in order to enable shipping over long distances and to prolong their shelf life.
In an attempt to provide some cooling to the packaged produce, the harvested fresh produce is typically packed into small, ventilated plastic containers that are ultimately purchased by the end consumer. These ventilated containers are commonly referred to as “clamshells”. Eight of these small, ventilated containers are placed into larger shipping trays that, in turn, are stacked on pallets for shipping. The conventional shipping trays can each include a bottom wall, a pair of opposed sidewalls, and a pair of opposed endwalls. The endwalls of these shipping trays commonly have a recessed portion along their length that permits the cooling air to pass into the ventilated containers. These conventional shipping trays have a length of twenty inches and a width of sixteen inches.
The conventional shipping trays are loaded onto the pallet in a “six-down” configuration. In the six-down configuration, a layer of the shipping trays is formed on the pallet by positioning six of the shipping trays so that their longitudinal axes extend in parallel directions and their recessed endwalls extend in parallel planes (See FIG. 11). These parallel endwall planes extend perpendicular to the directions that the sidewalls extend. The shipping trays are typically arranged on the pallet in multiple stacked layers until a predetermined number of shipping trays, such as forty-eight, is achieved. The most common pallet used in the produce industry is the forty-inch by forty-eight inch wooden pallet, and the vast majority of produce handling, storage and shipping equipment is designed around this sized pallet.
After the stacked shipping trays are loaded onto their respective pallet, the loaded pallet is moved to a forced air cooling chamber to cool and/or store the fresh produce. In the air cooling chamber, the pallets are arranged in rows against a wall that includes a vacuum fan. The rows are spaced apart and a canvas sheet is draped over the rows and the opposing end of the chamber to create an airflow channel. When the fan is turned on, it draws ambient cold air from the room through the vent openings in the trays carrying the produce. Typically, the room temperature is maintained at 32 degrees Fahrenheit and the target temperature for the produce is about 36.5 degrees Fahrenheit.
During the cooling process, the ambient cooling air arrives within each shipping tray by entering through one of its respective recessed endwalls. The cooling air then enters the individual containers carried by the tray in an attempt to cool the produce stored therein. As the air cools the produce, it picks up heat from the produce. The warmed air is eventually exhausted from the shipping tray through the opposite recessed endwall. After cooling the fresh produce in the shipping containers, the shipping containers are transported to grocery stores and fresh produce markets, where the fresh produce is sold to consumers.
The orientation and arrangement of the conventional six-down shipping tray configurations does not permit multi-directional cooling of the stored produce. As a result, the arrangement of pallets is limited. Additionally, the amount of cooling air entering the shipping trays may also be limited, thereby effecting the survival of the produce.